If she met the first man and agreed to have sex with him for money and then he subsequently didn't pay her, it was really a breach of contract. Certainly not rape.
If she agreed to have sex with the first two men for money and they subsequently didn't pay, it would be the same.
If she agreed to have sex with one or both of the first two men for money, but before the act occured they said they wouldn't be paying her and then had sex with her anyway against her will, it is rape.
If the 3rd and 4th man showed up and came to a financial agreement but subsequently didn't pay, again it's breach of contract.
If the 3rd and 4th man arrived and had sex with her against her will it's rape.
If any crimes occured then all the other men who were present and were aware of it are accomplices unless they attempted to stop it.
I basically break it down like this, if her issue is that she was not paid for something that was agreed to the crime is breach of contract (or perhaps theft if that's how the laws in her state are written). If there was sex that happened but was NOT agreed to it was rape. Each of the men should have his actions assessed individually and he can only be held accountable for his actions and any crime that he was aware of.
Yes, let’s look at this rationally.
If she is forced to have sex, it is rape.
Period.